聚1,2-丙二醇新戊二醇己二酸酯增塑性能的研究

将合成的聚1,2-丙二醇新戊二醇己二酸酯(简称PG-AA-NPG)聚酯增塑剂增塑PVC的试片制成复合材料,并进行耐迁移、DSC、力学性能、热稳定性能测试,分析PG-AA-NPG的综合性能,并且与加入DOP和市售聚酯增塑剂A的PVC试片进行对比.结果表明PG-AA-NPG的耐溶剂迁移性优于DOP;PVC/PG-AA-NP...     

Mechanical,thermal, and morphology properties of poly(lactic acid) plasticized with poly(ethylene glycol) and epoxidized palm oil hybrid plasticizer

Poly(lactic acid) (PLA) has received great attention recently due to its good physical and mechanical properties such as high tensile strength and modulus, good processability and biodegradability. In this study, low molecular weight poly(ethylene glycol) (PEG) and epoxidized palm oil (EPO) were used as hybrid plasticizers to improve toughness and ductility of PLA. Using the solubility parameter, a tentative evaluation of the hybrid plasticizer that could act as the most effective plasticizer for PLA has been performed and the obtained results have been corroborated with the materials physical properties. Excellent plasticizing effect was obtained by hybrid plasticizer PEG:EPO with ratio 2:1. Addition of PEG:EPO (2:1) hybrid plasticizer to PLA shows a significant improvement of 12,402%, compared to neat PLA. The improvement in flexibility and decrease in rigidity for the plasticized PLA is well evidenced by lower glass transition temperature (T_g) and tensile modulus values. In relation to the thermal stability, a decrease in thermal properties of the hybrid plasticized PLA was observed due to the volatility of the plasticizers. Scanning electron microscopy (SEM) shows that the hybrid plasticizer was turned PLA's smooth surface to fibrous structure and rough fracture surface. POLYM. ENG. SCI., 56:1169–1174, 2016. © 2016 Society of Plastics Engineers     

Recycling of Waste PET: Usage as Secondary Plasticizer for PVC

Postconsumer water bottle poly(ethylene terephthalate) (PET) flakes were depolymerized with ethylene glycol (EG) by the glycolysis reaction in the presence of zinc acetate as the catalyst. In the depolymerization reactions, different weight ratios of PET/EG were used. In order to obtain polyesters used as PVC plasticizers, these glycolysis products containing hydroxyl end groups were reacted with an adipic acid (AA)–containing diacid group at equivalent amounts. In order to obtain PVC plastisols, PVC was dispersed into a plasticizers' mixture composed of di-isooctyl phthalate (DOP) and polyester products by using a high-speed mixer (PVC/plasticizers, 65/35 w/w). For the preparation of plasticizer mixture polyester products were used at a weight ratio of 20%, 40%, 60% of DOP. Plasticized PVC sheets were prepared from plastisols and their glass transition temperatures (T_g), migration, and mechanical properties were determined. The results show that the polyester products obtained from glycolysis products of waste PET can be used as secondary plasticizers, with DOP for PVC.     

Evaluation of the Effect of Nanosilica on Thermal and Mechanical Properties of Metal–Metal and Metal–Glass Canola-Based Polyurethane/Nanosilica Adhesives

Nanocomposites with different concentration of nanofiller were prepared by adding nanosilica to the canola-based polyurethane matrix via in situ polymerization. The effect of nanosilica on the mechanical properties of adhesives was evaluated by tensile tests. Adhesive characteristics on metal–metal and metal–glass bondings were also evaluated by lap shear strength tests. Incorporation of nanosilica into the canola-based polyurethane enhanced both tensile and lap shear strength of synthesized adhesives. Also the effect of nanoparticles on glass transition temperature and thermal stability was investigated by differential scanning calorimetry and thermogravimetric analysis, respectively. The increase of nanosilica content in the polyurethane adhesives, thermal property of the nanocomposites improved.     

2,2‐Dinitro‐1,3‐Bis‐Nitrooxy‐Propane (NPN): A New Energetic Plasticizer

A new energetic plasticizer, 2,2‐dinitro‐1,3‐bis‐nitrooxy‐propane (NPN), has been characterized. Its high oxygen balance, +12.5%, and low glass transition temperature, −81.5 °C (midpoint), makes it very attractive as an energetic plasticizer in solid propellants. The ability of NPN to lower the glass transition temperature and viscosity of uncured PolyNIMMO has been studied and compared to other energetic plasticizers, such as BDNPA/F and butyl‐NENA. NPN has a similar plasticizing effect as butyl‐NENA, both on depressing the glass transition temperature and lowering the viscosity. To increase the poor thermal stability of NPN, several conventional nitrocellulose/nitroglycerine stabilizers were evaluated. Further work is however needed to find a more effective stabilizer.     

Succinate-based plasticizers: Effect of plasticizer structure on the mechanical and thermal performance of poly(vinyl chloride) plastic formulations

A new family of succinate-based plasticizers, consisting of molecules with a linear alkyl chain capped with n-alkyl succinates on both ends, was evaluated as potential bio-based plasticizers for stiff polymers. The influence of the central and side alkyl chain lengths on the mechanical and thermal properties as well as the migration behavior of poly(vinyl chloride) (PVC)/plasticizer blends was evaluated. The central chain length had the greatest influence on plasticizer performance, with shorter chains leading to blends with higher stress at break and surface hardness, whereas long chains produced softer blends. An optimum chain central length of five carbon atoms was observed, with longer chains leading to reduced compatibility and exudation of the plasticizer at higher plasticizer concentrations. The entire family of plasticizers performed comparably or better than the commercial plasticizer di(2-ethylhexyl) phthalate (DEHP) when incorporated into the blend at concentrations of 20–60 parts per hundred resin (phr). Overall, the succinate-based plasticizers/PVC blends all exhibited equal or improved tensile properties (by up to 77%), surface hardness (reduced by up to 43%), glass transition temperature (reduced by up to 11°C), and migration into organic media (reduced by up to 38%) when compared with blends with DEHP at 40 phr.     

Properties of a PVAc emulsion adhesive using a nonphthalate plasticizer obtained by condensation of 2-methylpropanal

The requirement to search for new plasticizers and coalescents for making water-based dispersion adhesives from poly(vinyl acetate) is of particular importance, especially now, after banning all kinds of toxic phthalates and restricting the use of glycol derivatives classified as volatile organic compounds. The poly(vinyl acetate) adhesive was synthesized using the eco-safe plasticizer – 3-hydroxy-2,2,4,-tri-methyl pentyl isobutyrate. The plasticizer was obtained by aldol condensation of 2-methylpropanal, byproduct of oxy synthesis from propylene. Its desirable properties were confirmed by comparing the composition of the adhesive comprising poly(vinyl acetate) as the principal component and the plasticizer as the additive. 3-hydroxy-2,2,4,-tri-methyl pentyl isobutyrate and commonly known plasticizers, such as: diisobutyl phthalate and diethylene glycol n-butyl ether acetate were used as the plasticizers in the experiment. The adhesives were compared in respect of the following parameters: dry weight, pH, viscosity, minimum film forming temperature, penetrability, setting time and stability in time. The test results indicate that 3-hydroxy-2,2,4,-tri-methyl pentyl isobutyrate can be used successfully as a plasticizer for making wood adhesives in the range from 2.0 to 2.5% of the adhesive formulation and for making bookbinding adhesives in the range from 4.7 to 5.6% of the adhesive formulation. This enables an about twofold reduction of the amount of the plasticizer, in comparison with the adhesive based on diisobutyl phthalate. 3-hydroxy-2,2,4,-tri-methyl pentyl isobutyrate can be used in dispersion adhesive formulations, thus replacing the undesirable, toxic phthalate esters and polyglycol derivatives classified as volatile organic compounds.     

In situ emulsion polymerization and characterization of PVAc nanocomposites including colloidal silica nanoparticles for wood specimens bonding

Polyvinyl acetate (PVAc) nanocomposites for wood adhesives containing different amounts of colloidal silica nanoparticles (CSNs) were synthesized via in situ one-step emulsion polymerization. The adhesion strength of wood specimens bonded by PVAc nanocomposites was investigated by the tensile test. Thermal properties of PVAc nanocomposites were also characterized by differential scanning calorimetry and thermogravimetric analysis. Rheological and morphological properties of the PVAc nanocomposites were investigated using rheometric mechanical spectrometry and field emission scanning electron microscopy (FESEM), respectively. The obtaining results showed that the shear strength of PVAc nanocomposite including 1 wt. % CSNs has the highest shear and tensile strength about 4.7 and 3.2 MPa, respectively. A small increment of T_g (~3 °C) and considerable increment of the ash content proved the enhancement of PVAc thermal characterization in the presence of CSNs. FESEM results showed uniform dispersion of nanoparticles throughout the PVAc matrix due to using the in situ emulsion polymerization process. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48570.     

原位乳液聚合法制备PVAc-OMMT纳米复合材料的性能研究

通过乳液聚合技术引发醋酸乙烯酯（VAc）在有机插层剂改性的蒙脱土（OMMT）中原位插层聚合,制备了一种新型聚合物-黏土纳米复合材料PVAc-OMMT。利用X射线衍射、透射电子显微镜和红外光谱研究了复合材料的结构和微观形态;利用热失重分析、差示扫描量热法研究了不同OMMT用量的复合材料的热稳定性;同时探讨了OMMT用量对材料力学性能的影响。结果表明,采用该方法得到了插层型纳米复合材料,且该纳米复合材料与相同条件下制备的纯聚醋酸乙烯酯（PVAc）相比,具有较高的玻璃化转变温度、优良的热稳定性和较好的力学性能;随着OMMT用量的增加,材料的起始热分解温度逐渐向高温方向移动,热稳定性提高;材料的拉伸强度随OMMT用量的增加出现先增加后减小的趋势,当OMMT用量为10 %（质量分数,下同）时,材料的拉伸强度达到最大值7.87 MPa。     

Cure and performance of castor oil polyurethane adhesive

Aiming at the development of sustainable materials, in this study, a biobased wood polyurethane adhesive (PUA), derived from castor oil (CO), was synthetized and its properties were compared with a conventional wood adhesive. Different NCO/OH ratios have been used to assess its effect on the properties of the ensuing adhesives. FTIR, and DMA were used to monitor the extent of reaction and the glass transition temperature of the adhesive, respectively. In turn, the wood bonding properties of the PUA over time were assessed by lap shear using pine wood specimens. Is was observed that the lap shear strength increases with the increase of the R_NCO/OH up to R_NCO/OH = 2.50. Above this ratio, the adhesive performance decreases slightly, due to the rigidity of the PUA. Comparison with a conventional wood adhesive showed that CO derived adhesives presented similar strength properties but required less time to develop the ultimate bonding strength. The chemical and thermal stability of the most promising CO adhesive was also assessed. Despite of being sensitive to the chemical environment, the castor oil derived adhesives presented higher thermal stability than conventional wood adhesives.Finally, the cure process of CO derived adhesives was studied by differential scanning calorimetry and the Kissinger and Ozawa methods were used to determine the activation energy (Ea). The former afforded a value for Ea = 80.55 and the latter Ea = 87.07 kJ mol⁻¹. Moreover, it was observed that the activation energy is dependent on the degree of cure, increasing slightly up to 0.6 and decreasing significantly afterwards.     

The effect of citrate esters as plasticizers on the thermal and mechanical properties of poly(methyl methacrylate)

Plasticizers play a key role in the formulation of polymers and in determining their physical properties and processability. This study examines the effects of citrate esters, triethylcitrate, and triacetine as plasticizers on the thermal and mechanical properties of poly(methyl methacrylate). The samples were characterized by differential scanning calorimetry, dynamical mechanical analysis, and mechanical testing under different plasticizer contents. Both citrate esters proved to be effective as plasticizers, DSC data for the triacetine additive fits with Fox equation. Microstructure and relaxation properties were studied by dynamic mechanical analysis where loss modulus shows clearly that absorbed plasticizer shifts the α‐transition to lower temperature and β‐relaxations associated to ester side groups are unchanged even up to 30 wt % plasticizer. Mechanical properties were evaluated with an Instron testing machine. Both additives produced (1) an initial plasticization, with a decrease in tensile strength and modulus; (2) an antiplasticization, reflected as an increase in tensile strength; and modulus and (3) a final plasticization, with a notable decrease in tensile strength and modulus and an increase in elongation where a 35 wt % of triethylcitrate added to the poly(methyl methacrylate) increased in 200% its elongation. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Poly(ε-caprolactone)-based additives: Plasticization efficacy and migration resistance

A family of poly(caprolactone) (PCL)-based oligomeric additives was evaluated as plasticizers for poly(vinyl chloride) (PVC). We found that the entire family of additives, which consist of a PCL core, diester linker, and alkyl chain cap, were effective plasticizers that improve migration resistance. The elongation at break and tensile strength of the blends made with the PCL-based additives were comparable to blends prepared with diisononyl phthalate (DINP), a plasticizer typically used industrially, and diheptyl succinate (DHPS), an alternative biodegradable plasticizer. Increasing concentration was found to decrease glass transition temperature (T_g) and increase elongation at break, confirming their role as functional plasticizers. We found that all of the PCL-based plasticizers exhibited significantly reduced leaching into hexanes compared to DINP and DHPS. The PCL-based plasticizers with shorter carbon chain lengths reduced leaching more than those with longer carbon chain lengths.     

三醋酸甘油酯增塑聚乳酸共混体系热力学及动态力学性质

用三醋酸甘油酯(TA c)增塑聚乳酸(PLA),研究了TA c对PLA力学性能的影响。当塑化剂添加到15%之后抗张强度从64M Pa下降到29.9M Pa,断裂伸长率同时从5.6%升高到243.1%,可以达到吹膜所要求的性质。用DSC和DM A研究了该共混体系的相容性,观察到随着TA c含量的增大,线性降低了PLA的Tg和Tm,并且塑化剂提高了分子链的迁移性,也使得体系的结晶度增大。在塑化剂含量为25%时,PLA已经被塑化剂所饱和,继续添加塑化剂可能会导致两相分离。     

Synthesis of low molecular weight poly(vinyl acetate) and its application as plasticizer

Poly(vinyl acetate), PVAc, with a degree of polymerization X_n = 10 was prepared by chain‐transfer radical polymerization using carbon tetrachloride and used as oligomeric plasticizer for commercial PVAc. However, the chlorinated chain ends cause a low thermal stability requiring mild Cl/H substitution. The product exhibits high thermal stability and excellent melt‐compounding properties. Blends of oligomeric and commercial PVAc show single glass transition temperatures which decrease with higher oligomer content and exhibit small negative deviations from Fox' linear additivity rule. This indicates plasticization and miscibility being mainly due to entropic effects. Injection‐moulded thick specimens show ductile behaviour at oligomer contents >10 wt %, while sheets with a thickness of 0.2–0.5 mm appear flexible already at 7.5 wt %. The oxygen permeability coefficients are an order of magnitude lower than those of low‐density polyethylene. Due to the sum of their properties, the plasticized sheets present a promising alternative in the preparation of barrier materials. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40226.     

Bio‐based polymeric resin from agricultural waste,neem (Azadirachta indica) seed cake,for green composites

Protein‐based polymeric resin has been developed from nonconventional and nonedible “neem seed cake (NSC)” that has very limited low‐value applications. Neem protein (NP), after extraction from defatted NSC, was used to prepare resin with two common plasticizers (glycerol and sorbitol). Properties of the NP resin sheets were evaluated as a function of plasticizer content. Increase of plasticizer content in NP sheets from 15 to 30% (w/w) enhanced fracture strain with a reduction in tensile strength, modulus, and thermal properties. Sorbitol‐plasticized NP sheets showed better mechanical and thermal properties in comparison to glycerol‐plasticized sheets. Effect of cross‐linking with glyoxal on the mechanical and thermal properties of sorbitol‐plasticized NP sheets was also investigated. Properties improved significantly at 10% (w/w) glyoxal content. Overall, with the enhanced properties of NP sheets, NP can be a viable alternative for edible protein‐based resin for making green composites. NP resin can also be used to replace some synthetic resins. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 10.1002/app.41291.     

Influence of the filler material on the thermal stability of one‐component moisture‐curing polyurethane adhesives

Filler materials are part and parcel for the adjustment of adhesives, in particular, their rheological and mechanical properties. Furthermore, the thermal stability of adhesives can be positively influenced by the addition of an expedient filler, with inorganic types common practice in most cases. In this study, one‐component moisture‐curing polyurethane adhesives for engineered wood products based on isocyanate prepolymers with different polymer‐filled polyether polyols were investigated with regard to the filler's potential to increase the thermal stability of bonded wood joints. The property changes due to the addition of fillers were determined by means of mechanical tests on bonded wood joints and on pure adhesive films at different temperatures up to 200°C. Additional analyses by atomic force and environmental scanning electron microscopy advanced the understanding of the effects of the filler. The tested organic fillers, styrene acrylonitrile, a polyurea dispersion, and polyamide, caused increases in the cohesive strength and stiffness over the whole temperature range. However, the selected filler type was hardly important with regard to the tensile shear strength of the bonded wood joints at high temperatures, although the tensile strength and Young's modulus of the adhesive films differed over a wide range. Prepolymers with a lower initial strength and stiffness resulted in worse cohesion, in particular, at high temperatures. This disadvantage, however, could be compensated by means of the filler material. Ultimately, the addition of filler material resulted in optimized adhesive properties only in a well‐balanced combination with the prepolymer used. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis of a novel polyester plasticizer based on glyceryl monooleate and its application in poly(vinyl chloride)

The use of bio‐based polymeric plasticizers could expand the application range of plasticized poly(vinyl chloride) (PVC) materials. In this study, a novel bio‐based polyester plasticizer, poly(glutaric acid‐glyceryl monooleate) (PGAGMO), was synthesized from glutaric acid and glyceryl monooleate via a direct esterification and polycondensation route. The polyester plasticizer was characterized by gel permeation chromatography, ¹H‐nuclear magnetic resonance, and Fourier‐transform infrared spectroscopy. The plasticizing effect of PGAGMO on PVC was investigated. The melting behavior, thermal properties, and mechanical properties of PVC blends were studied. The results showed that the PGAGMO could improve the thermal stability and reduce the glass transition temperature of PVC blends; when phthalates were substituted by PGAGMO in PVC blends, the thermal degradation temperature of PVC blends increased from 251.1°C to 262.7°C, the glass transaction temperature decreased from 49.1°C to 40.2°C, the plasticized PVC blends demonstrated good compatibility, and the decrement of the torque and the melt viscosity of PVC blends were conducive to processing. All results demonstrated that the PGAGMO could partially substitute for phthalates as a potential plasticizer of PVC. J. VINYL ADDIT. TECHNOL., 22:514–519, 2016. © 2015 Society of Plastics Engineers     

Physico-chemical properties of lignin–alginate based films in the presence of different plasticizers

A lignin–alginate blended film was prepared in the presence of three different plasticizers, viz. glycerol, epichlorohydrin (EPC) and poly(ethylene glycol) (PEG) and the effect of each plasticizer was studied on physico-chemical properties of the blended film. Lignin extracted from Acacia wood by alkali extraction process was blended with alginate to obtain lignin–alginate film in the presence of different plasticizers. A film plasticized with glycerol displayed higher solubility and swelling percentage as compared to EPC and PEG plasticized films. The highest tensile strength was observed for film plasticized with PEG, and none of the plasticizers made any significant change on the bursting strength of the film. Incorporation of lignin considerably improved the light barrier properties of the films. Fourier transform infrared spectroscopy study of films suggested the existence of hydrogen bonding between lignin–alginate in the presence of plasticizers. In addition, EPC plasticized film displayed highest thermal stability, as confirmed by thermogravimetric analysis. Further studies demonstrated that plasticizers significantly affected the physico-chemical properties of the blended films. In conclusion, lignin–alginate film plasticized with EPC presented better physico-mechanical and light barrier properties which could be used in packaging and coating applications.     

Understanding the Compatibility of the Energetic Binder PolyNIMMO with Energetic Plasticizers: Experimental and DFT Studies

The development of energetic binders with suitable energetic plasticizers is required to enhance the mechanical properties and to reduce the glass transition temperature of propellant and explosive formulations. The compatibility of the energetic binder poly(3‐nitratomethyl‐3‐methyloxetane) (polyNIMMO) with five different energetic plasticizers viz. bis(2,2‐dinitro propyl)acetal (BDNPA), dinitro‐diaza‐alkanes (DNDA‐57), 1,2,4‐butanetriol trinitrate (BTTN), N‐N‐butyl‐N ‘(2‐nitroxy‐ethyl) nitramine (BuNENA) and diethyleneglycoldinitrate (DEGDN) was studied by differential scanning calorimetry (DSC), rheology, and DFT methods. The results obtained for the pure binder were compared with the results obtained for the binder/plasticizer blend in regard of the decomposition temperature and the format of the peak indicated the compatibility of polyNIMMO with the plasticizers. The glass transition temperatures of the blends were determined by low temperature DSC and showed desirable lowering of glass transition temperature with single peak. The rheological evaluation revealed that the viscosity of the binder is considerably lowered by means of flow behavior upon addition of 20 % (w/w) plasticizer. The addition of BuNENA and DEGDN has maximum effect on the lowering of viscosity of polyNIMMO. The predicted relative trend of interaction energies between plasticizer and binder is well correlated with the corresponding trend of viscosity of binder/plasticizer blends. These experimental studies verified by theoretical methods are valuable to design practical blends of new plasticizers and binders.     

Thermal and mechanical properties of plasticized poly(L‐lactic acid)

Acetyl tri‐n‐butyl citrate (ATBC) and poly(ethyleneglycol)s (PEGs) with different molecular weights (from 400 to 10000) were used in this study to plasticize poly(L‐lactic acid) (PLA). The thermal and mechanical properties of the plasticized polymer are reported. Both ATBC and PEG are effective in lowering the glass transition (T_g) of PLA up to a given concentration, where the plasticizer reaches its solubility limit in the polymer (50 wt % in the case of ATBC; 15–30 wt %, depending on molecular weight, in the case of PEG). The range of applicability of PEGs as PLA plasticizers is given in terms of PEG molecular weight and concentration. The mechanical properties of plasticized PLA change with increasing plasticizer concentration. In all PLA/plasticizer systems investigated, when the blend T_g approaches room temperature, a stepwise change in the mechanical properties of the system is observed. The elongation at break drastically increases, whereas tensile strength and modulus decrease. This behavior occurs at a plasticizer concentration that depends on the T_g‐depressing efficiency of the plasticizer. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1731–1738, 2003